Creatinine, cystatin C, muscle mass, and mortality: Findings from a primary and replication population-based cohort.

BACKGROUND: Serum creatinine is used as initial test to derive eGFR and confirmatory testing with serum cystatin C is recommended when creatinine-based eGFR is considered less accurate due to deviant muscle mass. Low muscle mass is associated with increased risk of premature mortality. However, the associations of serum creatinine and cystatin C with muscle mass and mortality remain unclear and require further investigation to better inform clinical decision-making. METHODS: We included 8437 community-dwelling adults enrolled in the Dutch PREVEND study and 5033 in the US NHANES replication cohort. Associations of serum creatinine and/or cystatin C with muscle mass surrogates and mortality were quantified with linear and Cox proportional hazards regression, respectively. Missing observations in covariates were multiply imputed using Substantive Model Compatible Fully Conditional Specification. RESULTS: Mean (SD) age of PREVEND and NHANES participants (50% and 48% male) were 49.8 (12.6) and 48.7 (18.7) years, respectively. Median (Q1-Q3) serum creatinine and cystatin C were 71 (61-80) and 80 (62-88) µmol/L and 0.87 (0.78-0.98) and 0.91 (0.80-1.10) mg/L, respectively. Higher serum creatinine was associated with greater muscle mass, while serum cystatin C was not associated with muscle mass. Adjusting both markers for each other strengthened the positive relationship between serum creatinine and muscle mass and revealed an inverse association between serum cystatin C and muscle mass. In the PREVEND cohort, 1636 (19%) deaths were registered over a median follow-up of 12.9 (5.8-16.3) years with a 10-year mortality rate (95% CI) of 7.6% (7.1-8.2%). In the NHANES, 1273 (25%) deaths were registered over a median follow-up of 17.9 (17.3-18.5) years with a 10-year mortality rate of 13.8% (12.8-14.7%). Both markers were associated with increased mortality. Notably, when adjusted for each other, higher serum creatinine was associated with decreased mortality, while the association between serum cystatin C and increased mortality strengthened. The shapes of the associations in the PREVEND study and NHANES were almost identical. CONCLUSIONS: The strong association between serum creatinine and muscle mass challenges its reliability as GFR marker, necessitating a more cautious approach in its clinical use. The minimal association between serum cystatin C and muscle mass supports its increased use as a more reliable alternative in routine clinical practice.

Preoperative cognitive performance and its association with postoperative complications in vascular surgery patients: A prospective study.

BACKGROUND: Cognitive impairment affects nearly half of vascular surgery patients, but its association with postoperative outcomes remains poorly understood. This study explores the link between preoperative cognitive performance and postoperative complications, including postoperative delirium, in vascular surgery patients. METHODS: A prospective cohort study was conducted on vascular surgery patients aged ≥65. Preoperative cognitive performance was assessed using the Montreal Cognitive Assessment, and postoperative complications were evaluated using the Comprehensive Complication Index. The association was analyzed through multivariable logistic regression. RESULTS: Among 110 patients (18.2 â€‹% female, mean age 73.8 â€‹± â€‹5.7 years), cognitive impairment was evident in 48.2 â€‹%. Of the participants, 29 (26.3 â€‹%) experienced postoperative complications, among which 11 (10 â€‹%) experienced postoperative delirium. The adjusted odds ratio for the association between cognitive performance and postoperative complications was 1.19 (95 â€‹% CI 1.02-1.38; p â€‹= â€‹0.02). CONCLUSION: Worse preoperative cognitive performance correlated with increased odds of postoperative complications and postoperative delirium in vascular surgery patients.

Comparison of Various Functional Assessment Tools to Identify Older Patients Undergoing Aortic Aneurysm Repair at Risk for Postoperative Complications.

BACKGROUND: To estimate whether the benefits of aortic aneurysm repair will outweigh the risks, determining individual risks is essential. This single-center prospective cohort study aimed to compare the association of functional tools with postoperative complications in older patients undergoing aortic aneurysm repair. METHODS: Ninety-eight patients (≥65 years) who underwent aortic aneurysm repair were included. Four functional tools were administered: the Montreal Cognitive Assessment (MoCA); the 4-Meter Walk Test (4-MWT); handgrip strength; and the Groningen Frailty Indicator (GFI). Primary outcome was the association between all tests and 30-day postoperative complications. RESULTS: After adjusting for confounders, the odds ratio for MoCA was 1.39 (95% confidence interval [CI] 0.450; 3.157; P = 0.723), for 4-MWT 0.63 (95% CI 0.242; 1.650; P = 0.348), for GFI 1.82 (95% CI 0.783; 4.323, P = 0.162), and for weak handgrip strength 4.78 (95% CI 1.338; 17.096, P = 0.016). CONCLUSIONS: Weak handgrip strength is significantly associated with the development of postoperative complications after aortic aneurysm repair. This study strengthens the idea that implementing a quick screening tool for risk assessment at the outpatient clinic, such as handgrip strength, identifies patients who may benefit from preoperative enhancement with help from, for example, Comprehensive Geriatric Assessment, eventually leading to better outcomes for this patient group.

Age Is Just a Number for Older Kidney Transplant Patients.

The rise in the mean age of the global population has led to an increase in older kidney transplant (KT) patients. This demographic shift, coupled with the ongoing organ shortage, requires a nuanced understanding of which older adults are most suitable for KT. Recognizing the increased heterogeneity among older adults and the limitations of solely relying on chronological age, there is a need to explore alternative aging metrics beyond chronological age. In this review, we discuss the impact of older age on access to KT and postoperative outcomes. Emphasizing the need for a comprehensive evaluation that extends beyond chronological age, we explore alternative aging metrics such as frailty, sarcopenia, and cognitive function, underscoring their potential role in enhancing the KT evaluation process. Most importantly, we aim to contribute to the ongoing discourse, fostering an optimized approach to KT for the rapidly growing population of older adults.

Phase angle and donor type are determinants of coronary artery calcification in stable kidney transplant recipients at twelve months after transplantation.

BACKGROUND AND AIM: Coronary artery calcification (CAC) partially explains the excess cardiovascular morbidity and mortality after kidney transplantation. This study aimed to investigate determinants of CAC in stable kidney transplant recipients at 12 months post-transplantation. METHODS AND RESULTS: CAC-score was quantified by the Agatston method using non-contrast enhanced computed tomography, and age- and sex-standardized CAC-percentiles were calculated. Univariable and multivariable multinomial logistic regression was performed to study potential determinants of CAC. The independent determinants were included in multivariable multinomial logistic regression adjusting for potential confounders. 203 KTRs (age 54.0 ± 14.7 years, 61.1% male) were included. Participants were categorized into four groups according to CAC percentiles (p = 0 [CAC-score = 0], n = 68; p ≥ 1%-p ≤ 50% [CAC score = 29.0 (4.0-166.0)], n = 31; p > 50 ≤ 75% [CAC score = 101.0 (23.8-348.3)], n = 26; and p>75% [CAC score = 581.0 (148.0-1652)], n = 83). Upon multivariable multinomial logistic regression, patients with a narrower phase angle and patients who had received a graft from a deceased donor had a higher risk of being in the >75th CAC-percentile. CONCLUSIONS: This study identifies not only metabolic and transplant-related factors, but also phase angle, a composite marker of cell integrity, as an independent determinant of CAC at 12 months after kidney transplantation. This study offers new perspectives for future research into the value of bioelectrical impedance analysis in relation to vascular calcification in kidney transplant recipients.

Kidney Transplantation Improves Health-Related Quality of Life in Older Recipients.

Kidney transplantation is the best treatment for kidney failure in older patients. However, little is known regarding changes in health-related quality of life (HRQoL) from before to after transplantation and determinants of HRQoL in older kidney transplant recipients (KTR). We studied both, using data of older (≥65 years) patients waitlisted for kidney transplantation and older KTR 1 year after transplantation from the TransplantLines Biobank and Cohort Study. HRQoL was assessed using the SF-36 questionnaire. We included 145 older waitlisted patients (68% male, age 70 ± 4 years) and 115 older KTR at 1 year after transplantation (73% male, age 70 ± 4 years). Both mental (48.5 ± 8.4 versus 51.2 ± 7.7, p = 0.009) and physical (47.4 ± 8.5 versus 52.1 ± 7.2, p < 0.001) HRQoL were higher among included KTR, compared to the waitlisted patients. In paired analyses among 46 patients with HRQoL-data both before and after transplantation, there was a trend towards increased mental HRQoL (49.1 ± 8.4 to 51.6 ± 7.5, p = 0.054), and significantly increased physical HRQoL (48.1 ± 8.0 to 52.4 ± 6.7, p = 0.001) after transplantation. Among all assessed factors, the number of patient-reported immunosuppressive drug-related side effects was most strongly negatively associated with both mental and physical HRQoL. In conclusion, HRQoL is significantly higher among older KTR after kidney transplantation compared to older waitlisted patients.

Pre-donation Assessment of Cystatin C to Improve Prediction of Pre- and Post-Donation GFR in Potential Living Kidney Donors.

BACKGROUND AND HYPOTHESIS: Accurate estimation of glomerular filtration rate (GFR) is crucial in living kidney donation. While most eGFR equations are based on plasma creatinine, its levels are strongly influenced by muscle mass. Application of cystatin C (CysC)-based estimates before donation may improve both estimation of current GFR and prediction of post-donation GFR. METHODS: We assessed the performance of CKD-EPI equations based on creatinine (eGFRcreat-2009, eGFRcreat-2021), cystatin C (eGFRCysC-2012), or both (eGFRcombined-2012, eGFRcombined-2021) for estimating pre- and post-donation measured GFR in 486 living kidney donors. We subsequently focused on a subgroup of individuals with high/low muscle mass (25% highest/lowest 24-hour urinary creatinine excretion, sex-stratified and height-indexed). RESULTS: Pre-donation eGFRcombined 2012 and eGFRcombined 2021 showed the strongest associations with pre- and post-donation mGFR. Pre-donation eGFRcombined 2021 was most accurate for estimating both pre-donation (bias 0.01±11.9 mL/min/1.73m2) and post-donation mGFR (bias 1.3±8.5 mL/min/1.73 m2). In donors with high/low muscle mass, CysC-based equations (with or without creatinine) performed better compared to equations based on only creatinine. CONCLUSIONS: In conclusion, combined eGFR equations yielded a better estimate of pre- and post-donation mGFR, compared to estimates based on creatinine or CysC only. The added value of CysC seems particularly pronounced in donors with high or low muscle mass.

Pre-Transplant Hyperparathyroidism and Graft or Patient Outcomes After Kidney Transplantation.

The impact of pre-transplant parathyroid hormone (PTH) levels on early or long-term kidney function after kidney transplantation is subject of debate. We assessed whether severe hyperparathyroidism is associated with delayed graft function (DGF), death-censored graft failure (DCGF), or all-cause mortality. In this single-center cohort study, we studied the relationship between PTH and other parameters related to bone and mineral metabolism, including serum alkaline phosphatase (ALP) at time of transplantation with the subsequent risk of DGF, DCGF and all-cause mortality using multivariable logistic and Cox regression analyses. In 1,576 kidney transplant recipients (51.6 ± 14.0 years, 57.3% male), severe hyperparathyroidism characterized by pre-transplant PTH ≥771 pg/mL (>9 times the upper limit) was present in 121 patients. During 5.2 [0.2-30.0] years follow-up, 278 (15.7%) patients developed DGF, 150 (9.9%) DCGF and 432 (28.6%) died. A higher pre-transplant PTH was not associated with DGF (HR 1.06 [0.90-1.25]), DCGF (HR 0.98 [0.87-1.13]), or all-cause mortality (HR 1.02 [0.93-1.11]). Results were consistent in sensitivity analyses. The same applied to other parameters related to bone and mineral metabolism, including ALP. Severe pre-transplant hyperparathyroidism was not associated with an increased risk of DGF, DCGF or all-cause mortality, not supporting the need of correction before kidney transplantation to improve graft or patient survival.

Red blood cells as oxygen carrier during normothermic machine perfusion of kidney grafts: Friend or foe?

Renal ex vivo normothermic machine perfusion (NMP) is under development as an assessment tool for high-risk kidney grafts and as a means of achieving more physiologically accurate organ preservation. On-going hemolysis has been reported during NMP, as this technique relies on red blood cells for oxygen delivery. In this study, we confirm the occurrence of progressive hemolysis during 6-hour kidney NMP. NMP-associated erythrostasis in the glomeruli and in peri-glomerular vascular networks points to an interaction between the red blood cells and the graft. Continuous hemolysis resulted in prooxidative changes in the perfusate, which could be quenched by addition of fresh frozen plasma. In a cell-based system, this hemolysis induced redox stress and exhibited toxic effects at high concentrations. These findings highlight the need for a more refined oxygen carrier in the context of renal NMP.

Central Body Fat Distribution and Kidney Function after Living Kidney Donation.

BACKGROUND: In most screening guidelines, high body mass index (BMI) is considered a contraindication for kidney donation. New insights suggest that central body fat distribution might provide greater power in assessing kidney risk. This study aimed to determine whether BMI and central body fat distribution measures are associated with long-term kidney function after donor nephrectomy. We hypothesized that higher BMI, waist circumference (WC), and waist-to-height ratio (WHtR) were associated with lower kidney function long term after donation. METHODS: The study population consisted of living kidney donors. BMI, WC, and WHtR were measured during donor screening. The outcome postdonation kidney function was assessed using measured GFR (mGFR) (mGFR, 125 I-iothalamate infusion) at 3 months ( n =1042), 5 years ( n =556), and 10 years ( n =210) of follow-up. Primary multivariable linear regression analyses were performed with BMI and WC and secondary analyses with WHtR. Linear mixed models were performed to investigate change in postdonation eGFR. RESULTS: The donor age was 52±11 years, and 48% were male. The mean BMI was 26.1±3.6 kg/m 2 , and WC was 91±11 cm. Higher predonation BMI was associated with lower mGFR throughout follow-up: -1.35 (95% confidence interval [CI], -1.95 to -0.80), -1.55 (95% CI, -2.50 to -0.65), and -2.35 (95% CI, -4.10 to -0.60) ml/min per m 2 per 5 kg/m 2 higher BMI at 3 months, 5, and 10 years after donation, respectively, adjusted for sex, age, and predonation GFR. For WC, differences in mGFR were -1.30 (95% CI, -1.70 to -0.90), -1.50 (95% CI, -2.20 to -0.80), and -1.70 (95% CI, -3.00 to -0.50) ml/min per m 2 per 10 cm higher WC at 3 months, 5, and 10 years after donation, respectively. In male donors, BMI and WC were significantly associated with a negative postdonation change in eGFR. CONCLUSIONS: Higher BMI and WC were independently associated with lower GFR (long term) after living kidney donation.

Comparison of 2 Immunosuppression Minimization Strategies in Kidney Transplantation: The ALLEGRO Trial.

BACKGROUND: Evidence on the optimal maintenance of immunosuppressive regimen in kidney transplantation recipients is limited. METHODS: The Amsterdam, LEiden, GROningen trial is a randomized, multicenter, investigator-driven, noninferiority, open-label trial in de novo kidney transplant recipients, in which 2 immunosuppression minimization strategies were compared with standard immunosuppression with basiliximab, corticosteroids, tacrolimus, and mycophenolic acid. In the minimization groups, either steroids were withdrawn from day 3, or tacrolimus exposure was reduced from 6 mo after transplantation. The primary endpoint was kidney transplant function at 24 mo. RESULTS: A total of 295 participants were included in the intention-to-treat analysis. Noninferiority was shown for the primary endpoint; estimated glomerular filtration rate at 24 mo was 45.3 mL/min/1.73 m 2 in the early steroid withdrawal group, 49.0 mL/min/1.73 m 2 in the standard immunosuppression group, and 44.7 mL/min/1.73 m 2 in the tacrolimus minimization group. Participants in the early steroid withdrawal group were significantly more often treated for rejection ( P = 0.04). However, in this group, the number of participants with diabetes mellitus during follow-up and total cholesterol at 24 mo were significantly lower. CONCLUSIONS: Tacrolimus minimization can be considered in kidney transplant recipients who do not have an increased immunological risk. Before withdrawing steroids the risk of rejection should be weighed against the potential metabolic advantages.

Age Disparities in Access to First and Repeat Kidney Transplantation.

BACKGROUND: Evidence suggests that older patients are less frequently placed on the waiting list for kidney transplantation (KT) than their younger counterparts. The trends and magnitude of this age disparity in access to first KT and repeat KT (re-KT) remain unclear. METHODS: Using the US Renal Data System, we identified 2 496 743 adult transplant-naive dialysis patients and 110 338 adult recipients with graft failure between 1995 and 2018. We characterized the secular trends of age disparities and used Cox proportional hazard models to compare the chances of listing and receiving first KT versus re-KT by age (18-64 y versus ≥65 y). RESULTS: Older transplant-naive dialysis patients were less likely to be listed (adjusted hazard ratio [aHR] = 0.18; 95% confidence interval [CI], 0.17-0.18) and receive first KT (aHR = 0.88; 95% CI, 0.87-0.89) compared with their younger counterparts. Additionally, older patients with graft failure had a lower chance of being listed (aHR = 0.40; 95% CI, 0.38-0.41) and receiving re-KT (aHR = 0.76; 95% CI, 0.72-0.81). The magnitude of the age disparity in being listed for first KT was greater than that for re-KT ( Pinteraction < 0.001), and there were no differences in the age disparities in receiving first KT or re-KT ( Pinteraction = 0.13). Between 1995 and 2018, the age disparity in listing for first KT reduced significantly ( P < 0.001), but the age disparities in re-KT remained the same ( P = 0.16). CONCLUSIONS: Age disparities exist in access to both first KT and re-KT; however, some of this disparity is attenuated among older adults with graft failure. As the proportion of older patients with graft failure rises, a better understanding of factors that preclude their candidacy and identification of appropriate older patients are needed.

Transplant Outcomes After Exposure of Deceased Kidney Donors to Contrast Medium.

BACKGROUND: The administration of contrast medium is associated with acute kidney injury; however, the effect of exposure of a deceased organ donor to contrast medium on kidney transplant outcomes has been poorly studied. METHODS: A retrospective analysis of all deceased kidney donors between 2011 and 2021 and their corresponding recipients in the Netherlands was conducted. Multivariable analyses were performed to assess the associations between contrast medium exposure and delayed graft function (DGF)/graft survival. Linear mixed models were used to assess the differences in mean estimated glomerular filtration rate values in recipients 1 to 6 y after transplantation. RESULTS: In total, 2177 donors and 3638 corresponding kidney graft recipients were included. Twenty-four percent of the donors (n = 520) were exposed to contrast medium, corresponding to 23% of recipients (n = 832). DGF was observed in 36% (n = 1321) and primary nonfunction in 3% (n = 122) of recipients. DGF rates for donation after brain death (DBD) and donation after circulatory death (DCD) donors showed no significant effect of contrast medium exposure ( P = 0.15 and P = 0.60 for DBD and DCD donors, respectively). In multivariable analyses, contrast medium administration was not significantly associated with a higher DGF risk (odds ratio 1.06; 95% confidence interval, 0.86-1.36; P = 0.63) nor was a significant predictor for death-censored graft failure (hazard ratio 1.01; 95% confidence interval, 0.77-1.33; P = 0.93). Linear mixed models showed no difference in mean estimated glomerular filtration rate values in recipients 1 to 6 y posttransplantation ( P = 0.78). CONCLUSIONS: This study indicates that contrast medium administration in DBD and DCD donors has no negative effect on early and long-term kidney graft function.

Abdominal computed tomography measurements of body composition and waitlist mortality in kidney transplant candidates.

Body mass index is often used to determine kidney transplant (KT) candidacy. However, this measure of body composition (BC) has several limitations, including the inability to accurately capture dry weight. Objective computed tomography (CT)-based measures may improve pre-KT risk stratification and capture physiological aging more accurately. We quantified the association between CT-based BC measurements and waitlist mortality in a retrospective study of 828 KT candidates (2010-2022) with clinically obtained CT scans using adjusted competing risk regression. In total, 42.5% of candidates had myopenia, 11.4% had myopenic obesity (MO), 68.8% had myosteatosis, 24.8% had sarcopenia (probable = 11.2%, confirmed = 10.5%, and severe = 3.1%), and 8.6% had sarcopenic obesity. Myopenia, MO, and sarcopenic obesity were not associated with mortality. Patients with myosteatosis (adjusted subhazard ratio [aSHR] = 1.62, 95% confidence interval [CI]: 1.07-2.45; after confounder adjustment) or sarcopenia (probable: aSHR = 1.78, 95% CI: 1.10-2.88; confirmed: aSHR = 1.68, 95% CI: 1.01-2.82; and severe: aSHR = 2.51, 95% CI: 1.12-5.66; after full adjustment) were at increased risk of mortality. When stratified by age, MO (aSHR = 2.21, 95% CI: 1.28-3.83; P interaction = .005) and myosteatosis (aSHR = 1.95, 95% CI: 1.18-3.21; P interaction = .038) were associated with elevated risk only among candidates <65 years. MO was only associated with waitlist mortality among frail candidates (adjusted hazard ratio = 2.54, 95% CI: 1.28-5.05; P interaction = .021). Transplant centers should consider using BC metrics in addition to body mass index when a CT scan is available to improve pre-KT risk stratification at KT evaluation.

Health-related quality of life is linked to the gut microbiome in kidney transplant recipients.

Kidney transplant recipients (KTR) have impaired health-related quality of life (HRQoL) and suffer from intestinal dysbiosis. Increasing evidence shows that gut health and HRQoL are tightly related in the general population. Here, we investigate the association between the gut microbiome and HRQoL in KTR, using metagenomic sequencing data from fecal samples collected from 507 KTR. Multiple bacterial species are associated with lower HRQoL, many of which have previously been associated with adverse health conditions. Gut microbiome distance to the general population is highest among KTR with an impaired physical HRQoL (R = -0.20, P = 2.3 × 10-65) and mental HRQoL (R = -0.14, P = 1.3 × 10-3). Physical and mental HRQoL explain a significant part of variance in the gut microbiome (R2 = 0.58%, FDR = 5.43 × 10-4 and R2 = 0.37%, FDR = 1.38 × 10-3, respectively). Additionally, multiple metabolic and neuroactive pathways (gut brain modules) are associated with lower HRQoL. While the observational design of our study does not allow us to analyze causality, we provide a comprehensive overview of the associations between the gut microbiome and HRQoL while controlling for confounders.

Perioperative Factors Associated With Postoperative Delirium in Patients Undergoing Noncardiac Surgery: An Individual Patient Data Meta-Analysis.

Importance: Postoperative delirium (POD) is a common and serious complication after surgery. Various predisposing factors are associated with POD, but their magnitude and importance using an individual patient data (IPD) meta-analysis have not been assessed. Objective: To identify perioperative factors associated with POD and assess their relative prognostic value among adults undergoing noncardiac surgery. Data Sources: MEDLINE, EMBASE, and CINAHL from inception to May 2020. Study Selection: Studies were included that (1) enrolled adult patients undergoing noncardiac surgery, (2) assessed perioperative risk factors for POD, and (3) measured the incidence of delirium (measured using a validated approach). Data were analyzed in 2020. Data Extraction and Synthesis: Individual patient data were pooled from 21 studies and 1-stage meta-analysis was performed using multilevel mixed-effects logistic regression after a multivariable imputation via chained equations model to impute missing data. Main Outcomes and Measures: The end point of interest was POD diagnosed up to 10 days after a procedure. A wide range of perioperative risk factors was considered as potentially associated with POD. Results: A total of 192 studies met the eligibility criteria, and IPD were acquired from 21 studies that enrolled 8382 patients. Almost 1 in 5 patients developed POD (18%), and an increased risk of POD was associated with American Society of Anesthesiologists (ASA) status 4 (odds ratio [OR], 2.43; 95% CI, 1.42-4.14), older age (OR for 65-85 years, 2.67; 95% CI, 2.16-3.29; OR for >85 years, 6.24; 95% CI, 4.65-8.37), low body mass index (OR for body mass index <18.5, 2.25; 95% CI, 1.64-3.09), history of delirium (OR, 3.9; 95% CI, 2.69-5.66), preoperative cognitive impairment (OR, 3.99; 95% CI, 2.94-5.43), and preoperative C-reactive protein levels (OR for 5-10 mg/dL, 2.35; 95% CI, 1.59-3.50; OR for >10 mg/dL, 3.56; 95% CI, 2.46-5.17). Completing a college degree or higher was associated with a decreased likelihood of developing POD (OR 0.45; 95% CI, 0.28-0.72). Conclusions and Relevance: In this systematic review and meta-analysis of individual patient data, several important factors associated with POD were found that may help identify patients at high risk and may have utility in clinical practice to inform patients and caregivers about the expected risk of developing delirium after surgery. Future studies should explore strategies to reduce delirium after surgery.

External ureteric stent versus internal double J stent in kidney transplantation: a retrospective analysis on the incidence of urological complications and urinary tract infections.

Introduction: Urologic complications (UCs) and urinary tract infections (UTIs) are common after kidney transplantation. Intraoperative stent placement at the vesicoureteric anastomosis reduces UC risk, but increases UTI risk. Methods: In 2014 our stenting protocol changed from external ureteric stent (ES) to internal double J stent (DJ). We retrospectively studied the occurrence of UCs and UTIs in relation to ES or DJ in 697 kidney recipients. Methods: An ES was used in 403 patients (57.8%), in 294 (42.2%) a DJ. ES was removed 7-12 days and DJ 3-4 weeks post-operative. Induction immunosuppression was the same in both groups. Primary outcomes at 6 months follow-up were UC (urinary leakage/ureter stenosis) and UTI; they were related to stenting procedure and clinical and transplant characteristics. The incidence of UCs was similar for ES (8.4%) and DJ (6.8%), p=0.389. ES use was a significant risk factor for UTI (OR 1.69 (1.15-2.50), p=0.008). Post-transplant hospitalization was significantly shorter in the DJ group. Despite more acute rejection episodes with ES (ES/DJ: 16.4%/6.1%, p<0.001), no clinical relevant differences in graft outcomes existed. Discussion: A DJ is, compared to ES, associated with a lower incidence of UTIs and comparable occurrence of UCs and is therefore the preferred technique for stenting the vesicoureteric anastomosis.

Validity of computed tomography defined body composition as a prognostic factor for functional outcome after kidney transplantation.

BACKGROUND: The prevalence of sarcopenia is markedly higher in kidney transplant candidates than in the general population. It is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength, which increases the risk of adverse postoperative outcomes. METHODS: We studied the impact of computed tomography defined preoperative sarcopenia, defined as a skeletal muscle index below age and gender specific cut-off values, on postoperative physical functional outcomes (grip strength, 4-m walking test, timed up and go, and sit to stand) at 6 months follow up. RESULTS: A total of 107 patients transplanted between 2015 and 2019 were included in this single-centre study. Mean age was 60.3 (±13.1), and 68.2% of patients were male. Ten patients (9.4%) were identified as sarcopenic. Sarcopenic patients were younger (55.6 (±15.1) vs. 60.8 (±12.9) years), more likely to be female (60.0% vs. 28.9%), and had an increased dialysis vintage (19 [2.5-32.8] vs. 9 [0.0-21.0] months) in comparison with their non-sarcopenic counterparts. In univariate analysis, they had a significantly lower body mass index and skeletal muscle area (P ≤ 0.001). In multivariate regression analysis, skeletal muscle index was significantly associated with grip strength (ß = 0.690, R2  = 0.232) and timed up and go performance (ß = -0.070, R2  = 0.154). CONCLUSIONS: We identified a significant association between sarcopenia existing pre-transplantation and poorer 6 months post-transplantation physical functioning with respect to hand grip strength and timed up and go tests in kidney transplant recipients. These results could be used to preoperatively identify patients with an increased risk of poor postoperative physical functional outcome, allowing for preoperative interventions to mitigate these risks.

PREhabilitation of CAndidates for REnal Transplantation (PreCareTx) study: protocol for a hybrid type I, mixed method, randomised controlled trial.

INTRODUCTION: Kidney transplant candidates (KTCs) need to be in optimal physical and psychological condition prior to surgery. However, KTCs often experience compromised functional capacity which can be characterised as frailty. Prehabilitation, the enhancement of a person's functional capacity, may be an effective intervention to improve the health status of KTCs. The PREhabilitation of CAndidates for REnal Transplantation (PreCareTx) study aims to examine the effectiveness of a multimodal prehabilitation programme on the health status of KTCs, and to explore the potential of implementation of prehabilitation in daily clinical practice. METHODS AND ANALYSIS: This study uses a single centre, effectiveness-implementation hybrid type I study design, comprised of a randomised controlled trial and a mixed-methods study. Adult patients who are currently on the transplant waiting list or are waitlisted during the study period, at a university medical centre in The Netherlands, will be randomly assigned to either prehabilitation (n=64) or care as usual (n=64) groups. The prehabilitation group will undergo a 12-week home-based, tailored prehabilitation programme consisting of physical and/or nutritional and/or psychosocial interventions depending on the participant's deficits. This programme will be followed by a 12-week maintenance programme in order to enhance the incorporation of the interventions into daily life. The primary endpoint of this study is a change in frailty status as a proxy for health status. Secondary endpoints include changes in physical fitness, nutritional status, psychological well-being, quality of life and clinical outcomes. Tertiary endpoints include the safety, feasibility and acceptability of the prehabilitation programme, and the barriers and facilitators for further implementation. ETHICS AND DISSEMINATION: Medical ethical approval was granted by the Medical Ethics Committee Groningen, Netherlands (M22.421). Written informed consent will be obtained from all participants. The results will be disseminated at international conferences and in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, NCT05489432.